I’m still looking around for intelligent flight batteries in the 6s range but apparently there are
no other options then the DJI ones. However we still can’t readout the I2C port of those batteries
or does some one has different informations?
Are there other 6s intelligent flight batteries available?

I popped open a busted Inspire 1 battery earlier this year and found it has the TI BQ78350 and BQ76930 battery management chipset which supports SMBUS. You can see these, as well as two test points labeled “SMBD” and SMBC" near the BQ78350 in the image of the PCB here: http://i.imgur.com/bjeAfxz.jpg

The bus then goes to an MSP430 which seems to be connected to the two pads on the battery’s connector (through opto-isolators if I remember correctly). It’s Probably translating the SMBUS into some proprietary protocol DJI uses (I didn’t have a scope or logic analyzer at the time so I can’t say for sure).

If you really want to use Inspire 1 batteries with SMBUS, you might try disconnecting the external data pins from the MSP430 and running them directly to the SMBUS test points near the BQ78350. There are two jumper links to the right of the test pads that you will need to break to disconnect the MSP430 from the BQ78350.

I don’t know if I can get that battery back as it belongs to the local university, but if I can I’ll give this a try. Won’t be any time soon, however.

I have disassembled the batteries of Inspire 1 (TB-47) and Inspire 2 (TB-50) and connected a logic analyser to sniff the communication between the drone and the battery…
If anyone is interested on working out the communication protocol, feel free to ask me for the logic data I sampled.

We have developed a prototype battery management board that is capable of 6s through 12s battery packs.
It measures all of the cell voltages as well as the pack terminal voltage and current; and reports them via a CANbus protocol that is compatible with the Pixhawk CAN interface. It also integrates current versus time to do fuel gauging as well. We are working on modifying Arducopter to be able to read the cell/pack voltages via CAN and (eventually) log or report them back via MAVLINK telemetry. The BMS hardware and CAN interface is built, tested, and working; the Arducopter software end still needs significant work. Please contact me if you are interested in possibly being a development partner and helping us to prove out our technology prior to a product launch.

The board communicates with our Hybrid-Electric gen-set via CAN bus, and also makes all the battery information available to the Pixhawk flight controller via the CAN bus. The Pixhawk code to read the CAN message has not yet been completed, but should be fairly straightforward for a Pixhawk developer with CAN communications experience.

Since we are building them in only small quantities right now they are fairly expensive (>$1000 each), and are not really available as a “product” since we can’t support them on a one-off basis. We are interested in working with partners who would have a need for multiple units eventually in which case we can provide partner support to get a unit working for an application that may go to higher volume. We can also license the design and software to interested 3rd parties as well.

Sorry for being misleading, previously I was speaking about BT-50 for DJI Inspire 2 Smart Battery, it’s UART. But it’s nothing to do about Intelligent flight batteries like PH4 batteries for DJI Phantom 4. So it’s still actual to parse the Intelligent flight battery sniffs. By the way there’s no private message feature on this forum…

I just entered the forum. I’m building a custom drone and would like to use the tb47s batteries for my custom build as they are really convenient. I have the brackets that the m600 uses that also has the cables for the serial connection of the batteries. However when i connect 2 of them parallel (bus and + -) and turn one of the batteries on it starts charging the other battery in stead of turning the other battery on. Is there someone here that can help me out here? I just want them to turn on when i power one of the batteries.
Hope this is something that can be resolved.